Figure4. Out-put of model in terms of (a) concentration of ethanol and diethyl ether as a function of time, (b) time interval of 27000 s for concentration of ethanol and diethyl ether as a function of adsorbent length and (c) temperature profile variation versus time at different length of bed for feed flow rate of 333 kmol/h
One of effective parameters in design of adsorption bed is gas superficial velocity. For constant feed flow rate, one can easily calculate diameter of adsorption bed based on gas velocity and feed flow rate. In adsorption processes, it is evident that gas superficial velocity greatly enhances energy and mass transfer by decreasing the external film around the adsorbent. 19Increase in superficial velocity is favored till meeting maximum permissible pressure drop, near to the criterion of 7.50kPa/m. 17, 20Figure 5 shows variation of Reynolds number, the Peclet number and velocities with time.